openssl_seal

Description

openssl_seal() seals (encrypts)
data by using RC4 with a randomly generated
secret key. The key is encrypted with each of the public keys
associated with the identifiers in pub_key_ids
and each encrypted key is returned
in env_keys. This means that one can send
sealed data to multiple recipients (provided one has obtained their
public keys). Each recipient must receive both the sealed data and
the envelope key that was encrypted with the recipient's public key.

Parameters

data

sealed_data

env_keys

pub_key_ids

Return Values

Returns the length of the sealed data on success, or FALSE on error.
If successful the sealed data is returned in
sealed_data, and the envelope keys in
env_keys.

See Also

User Contributed Notes 3 notes

"seals (encrypts) data by using RC4 with a randomly generated secret key"It should be noted that the randomly generated secret key is 128 bits long (openssl: EVP_rc4(void): RC4 stream cipher. This is a variable key length cipher with default key length 128 bits.)

openssl_seal() can work well when you need to pass data securely to other platforms / languages. What openssl_seal() does is;

1. Generate a random key2. Encrypt the data symmetrically with RC4 using the random key3. Encrypt the random key itself with RSA using the public key / certificate4. Returns the encrypted data and the encrypted key

So to decrypt the steps are simply;

1. Decrypt the key using RSA and your private key2. Decrypt the data using RC4 and the decrypted key